The CTP Technology: Blue, Thermal and now Violet !
CTP has been in the graphic world for almost ten years now and we have seen lots of new laser types since (UV, 488nm Argon-Ion, 532nm NdYag, 830nm Thermal Diodes, 1064nm Thermal Yag). All have been developed for graphic arts but did not really get a mass market and therefore are still rather expensive in buying and replacing. With these diode or laser technologies we have seen lots of different plate types and technologies and have gone through several development stages.
For the plates it is safe to say that despite ongoing developments we have stable products for green and thermal lasers. The market has proven that the best quality is provided by NdYag lasers imaging on silver based plates in internal drum machines and that the highest runs come from baked thermal plates.
With approx. 3500 installed CTP systems worldwide we have now reached approx. 8-9% of the overall plate volume to be imaged digitally on CTP devices. During the last two years it looked like everything would go thermal due to the daylight handling of high run length plates, accepting the disadvantages of this technology. Although these red diodes itself are cheap, the whole optical system (with 64 or even 240 diodes) represents a very complicated and expensive replacement part with a relatively short lifetime: the sensitivity of the plates define the speed of the machine which is rather slow and only makes sense in high resolution imaging, with very long run lengths or with the use of UV inks which require baked plates.
The Future of the commercial market in Violet.
But now comes the violet time and we quote Kurt K.Wolf out of Seybold to see what is behind it: Enter violet. With the advent of the DVD player, new violet laser diodes became available, emitting 5mWatt power at 400-410nm wavelengths, which is what silver plates require to be imaged by an internal drum plate setter. These new laser diodes have a narrower beam, which means the spinner can be smaller and, therefore, rotate faster. The price for these diodes is lower and the exact life expectancy is not known yet, but Agfa claims that it will be several thousand hours. But, most important, violet diodes imaging speed is potentially faster than external drum thermal platesetters. The new Agfa Lithostar Ultra plate is sensitive at 410nw, and desensitized for daylight, which means that the plates can be used in yellow room light. We expect other manufacturers (rumors to include Fujifilm) will come up with similar plates as well.
The Effect on Krause Laserstar CTP.
From Drupa 200 onwards the new violet laser diode technology offers a variety of advantages for the Krause LaserStar CTP systems which can be delivered or upgraded now. The violet laser diodes are less expensive, only one violet laser diode per platesetter is needed. The laser beam is modulated directly and runs through a simple and small optical system which can operate with a small and therefore much faster monogon mirror due to the 405nm wavelength and the related narrow beam. The LaserStar internal drum system is ideal fir this new imaging technology and the violet laser diode module is ready and available.
Krause have an easy to replace pre-assembled and adjusted module which will have an expected lifetime of approx. 3000-5000 pure imaging hours which sounds comparable to NdYag laser modules that currently run 5000 hours, but those are switched on even if the machine is in standby mode between exposures, while a violet laser diode is only active during the exposure.